This invention relates to internal combustion engines and, more particularly, to configurations of engine cylinder inlet ports for conducting air or air-fuel mixture to the cylinders of such engines.
It is well known in the art of internal combustion engines to provide for each cylinder an inlet port which opens through the closed end of its respective cylinder and is controlled by a poppet inlet valve. The port provides a passage way by which air or air-fuel mixture are conducted to the cylinder for burning, expansion and subsequent exhaust in known manner.
The inlet port and the associated poppet valve restrict, to an extent dependent on their size and shape, the amount of air or mixture flow which can be drawn into the engine cylinder during the induction stroke when the intake poppet valve is closed. Thus, the valves and their associated ports are generally made as large as possible within the limits imposed by other engine requirements and the inlet ports are made as short and free from turns and protuberances as is consistent with other design considerations in order to minimize to the extent possible the restriction to airflow provided by the port and associated valve. Often, however, it is necessary for the best overall engine configuration to provide a relatively sharp angular bend in the inlet port to connect a throat portion that opens through the cylinder closed end with an entrance portion extending laterally out through a side wall of the port-defining cylinder head or engine block.